The present invention relates to an image processing method and apparatus capable of separating a plurality of colors from a color image signal and, more particularly, to a digital copy machine which separates red component and black component, for instance, from the read color image signal, then forms an image by expressing the red component with red color and the black component with black color.
A technique suggested according to U.S. Ser. No. 07/671,450 is, for a digital copy machine, to read a color original image by using a photoelectric converting element, such as a color CCD, and to discriminate an area in accordance with color information on the original image, then to express the discriminated area with a color which differs from a color representing the rest area (red and black, for instance).
Further, there is suggested a technique disclosed to separates a red component and a black component, for instance, from the read color image signal, then expresses the original image by using two colors which differ from each other. For example, the image is formed by using a red color for the red component and a black color for the black component.
An image forming apparatus, which forms an image by discriminating areas and expressing the areas with colors which differ from each other, is able to express a red character with red color in a case where the red character is included in a part of an original image which includes black-and-white. However, the apparatus is not suitable to express a full-color image since it forms an image by expressing each area with red color or black color.
Further, there are problems with an image forming apparatus which separates two color components from a full-color image and then expresses the image with two colors differing from each other, as described below.
(1) Colors for separation can not be designated or changed, since color components being separated from an original are limited to predetermined two colors;
(2) Colors for separation and colors for output can not be designated or changed freely, since the colors for separation and colors for output of image data which is separated in accordance with the colors for separation are limited to predetermined two colors for the entire image;
(3) If quality for expressing an image is to be improved by designating and changing colors for separation and colors for output of image data which is separated in accordance with the colors of separation, since more items needs to be designated, the operation of the apparatus becomes complicated and troublesome, and operational mistakes can result in many miss-copying; and
(4) The image forming with red color is limited to the red component area of the original image, thus most part of the original image is formed with black color and quality for expressing image is low. Therefore an advantage of forming an image with two colors is not obtained.
Accordingly, it is a purpose of the present invention to provide an image processing apparatus and method which partially or totally solve the aforementioned problems relating to a digital copy machine that forms an image with two colors differing from each other.
The foregoing object is attained by providing an image processing apparatus comprising: detecting means for detecting hue of color image information; first deciding means for deciding a color component to be separated from the color image information in correspondence with the hue detected by the detecting means; second deciding means for deciding an output color corresponding to the color component decided by the first deciding means; separating means for separating image information with at least two color components from the color image information based on a result by the first deciding means; and output means for outputting the image information for the color component which is separated by the separating means as image information on the output colors decided by the second deciding means.
The foregoing object is also attained by providing an image processing method comprising: a detecting step of detecting hue of color image information; a first deciding step of deciding a color component to be separated from the color image information in correspondence with the hue detected at the detecting step; a second deciding step of deciding an output color corresponding to the color component decided at the first deciding step; a separating step of separating image information on at least two color components from the color image information based on a result at the first deciding step; and an output step of outputting the image information on the color components which is separated at the separating step as image information on the output colors decided at the second deciding step.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.